Ed Brayant wrote a great story based on "Them", called "giANTs"... only in this case, the gigantisim in the insects is diliberately induced... as a way to kill them. The insects grow, and die, their body sturctures unable to support their increasing mass. I think it's reprinted in his collection "Cinnebar."

What if...

What if a monster appeared, some form of alien perhaps, who shared Dracula's chief weapon? Sexual attraction.